Widespread access to predictive models in the motor system: a short review

Abstract

Recent behavioural and computational studies suggest that access to internal predictive models of arm and object dynamics is widespread in the sensorimotor system. Several systems, including those responsible for oculomotor and skeletomotor control, perceptual processing, postural control and mental imagery, are able to access predictions of the motion of the arm. A capacity to make and use predictions of object dynamics is similarly widespread. Here, we review recent studies looking at the predictive capacity of the central nervous system which reveal pervasive access to forward models of the environment.

The role of kinematic redundancy in adaptation of reaching

“…There was no difference in these components across a similar range of reaches for the control group. Although this result does not argue against the role of internal models in learning and adaptation in general, or for other functional tasks (Davidson and Wolpert 2005), it does raise questions about the nature of such models.…”

“…Taken together, these results provide further evidence that the use of equivalent solutions to joint coordination, which reflects flexibility of coordination processes, is a typical feature of the control system and that this feature is enhanced when the system is forced to adapt to novel dynamics (compare these results, for example, with those of Scholz et al 2002 for a very different task). These results would appear to be inconsistent with the likely predictions of an account of adaptation based on learning a detailed model of the dynamics of limb-environment interaction (Davidson and Wolpert 2005;Hwang and Shadmehr 2005). Future iterations of internal models of adaptation will need to account for the differential changes in joint variance, i.e.…”

“…This prediction has implications for explanations of motor adaptation based on internal models. If internal models are created or optimized during learning (Davidson and Wolpert 2005;Hwang and Shadmehr 2005;Shadmehr and Mussa-Ivaldi 1994), then decreases in V ORT with practice can be expected. However, changes in V UCM would not be predicted because such changes, reflecting the use of many equivalent combinations of motor elements, are irrelevant to task success.…”

How Brains Make Mental Models

“…Hence logicbased approaches to abduction seem impotent to address what Peirce took to be a major feature of this kind of inference (cf. [45,4]). Thagard [4] gave an account of how new concepts can be generated in the context of explanatory reasoning, but this account only applied to verbal concepts represented as frames with slots and values.…”

“…Recent theoretical explanations of this capacity understand motor control as representational and computational, requiring mental models (see e.g. [4,47]). What follows is a concise, simplified, synthesis of their accounts.…”